TIP #394: PLATFORM-INDEPENDENT HANDLING OF CONTEMPORARY MICE 
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 Version:      $Revision: 1.1 $
 Author:       Andreas Leitgeb <avl_at_logic.at>
 State:        Draft
 Type:         Project
 Tcl-Version:  8.7
 Vote:         Pending
 Created:      Wednesday, 30 November 2011
 URL:          http://tcl.activestate.com/cgi-bin/tct/tip/394.html
 Post-History: 

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 ABSTRACT 
==========

 This TIP proposes a change to Tk's Events such as to support new 
 features of modern pointer devices (mice) in a platform-independent 
 way. 

 RATIONALE 
===========

 Modern pointing devices (mice) do have more controls beyond the 
 standard three buttons and one-dimensional scrolling gadget. They often 
 have any of these as well: 

     * Tilt-able scroll wheel 

     * A second wheel for horizontal scrolling 

     * A scroll-ball rather than a scroll wheel (see Apple's 
       "mightymouse") 

     * Additional "forward" and "backward" buttons 

     * even more buttons... 

 On Linux platform, bind'ing on <Button> will catch all(?) or these (and 
 "%b" gives an ordinal number which allows for some heuristic 
 recognition). But even on Linux, it is not possible to bind 
 specifically to e.g. <Button-8>, or to <B8-Motion> kind of events. 

 On Windows platform, the system offers different types of events for 
 certain different controls. An app would e.g. register extra to receive 
 horizontal scroll events and those extra buttons. (This is gathered 
 from hearsay.) 

 PROPOSAL 
==========

 Just like the MouseWheel event that was added to Tk in response to 
 wheel-mice filling the market, we'd have to define new events for each 
 new control. 

 For legacy-reasons, the dichotomy between vertical scroll wheel and 
 buttons 4 and 5 will need to be preserved, maybe as well as the buttons 
 6 and 7 for horizontal scrolling. 

 Any extra buttons could then be either named "X1", "X2", "X3", ... or 
 numbered 8, 9, 10, ... which would reflect as bind events <Button-8> or 
 <Button-X1>, but also <B8-Motion> or <BX1-Motion> 

 For horizontal scrolling, <MouseWheelHoriz> would be the preferred way 
 for cross-platform apps, but depending on whether "4 and 5" button 
 events are already emulated for scrolling on windows, it would be 
 worthwhile to also emulate "6 and 7" button events for horizontal 
 wheel-activity. 

 At this stage of this TIP the decision isn't yet made. 

 COPYRIGHT 
===========

 This document has been placed in the public domain. 

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